Lancaster Farming – Author:
One of the buzzwords in the hemp space this year is autoflower. But what is it and why would you want to grow it? This episode answers those questions and a whole lot more with a roundtable panel discussion about autoflowering varieties of industrial hemp with Lancaster County farmer Steve Groff, Atlas Seed Co. Breeder Joe Ullman, and Atlas Seed Co. grower Ryan Power.
And here’s what we cover:
• The differences between autoflower and photoperiod hemp
• Is cloning an option
• Expected feminization rates
• When does the flowering cycle start
• Best time to plant
• Recommended spacing
• Transplanting vs. direct seeding
• Optimal feeding plan
• Expected yields
• Cannabinoid percentages and more.
Autoflower FAQ, provided by Atlas Seed Co.
What is the difference between autoflowering genetics and normal clone or full term varieties?
In short, autoflowering varieties, otherwise known as day neutral genetics or Cannabis ruderalis, begin their flowering phase automatically, regardless of changes in light cycles; normal, full term, clonally propagated Cannabis sativa and Cannabis indica varieties “flip” to their flowering phase when they exposed to 12 hours of darkness.
Can you take cuttings (clones) of autoflowering varieties?
No, autoflowering cannabis does not allow for cuttings to be taken and therefore must be started from seed and be pollinated to further genetic lines.
What can I expect in terms of the feminization rate of Atlas Seed genetics?
The seeds we offer will show between 1 and 1500 to 1 and 2500 male to female ratio in their respective population. That means between 99.93% and 99.96% will female. We also offer lab test certified feminized seed on key lots to verify the quality of our feminization process.
When can I expect my auto plants to begin their flowering cycle?
Roughly speaking (again growing climate and genetically dependant), autoflowering plants finish their vegetative cycle between weeks 3-5, will continue to stack flowering sites between weeks 3-8, and will see their flowering sites bulk up, densify, and finish in weeks 8-12. For those used to full term and yet unaccustomed to autoflowering cannabis, remain calm until the end of the cycle and watch in marvel as plants continue to increase their flowering yield and cannabinoid content up until the day of harvest!
When is the best time to plant autoflowering varieties?
This is highly dependent on your local climatic conditions, but the rule of thumb is that autos prefer long, dry, sunny days. If you are going for one solid, high yielding harvest then planting as soon as summer soil temperatures stabilize is the way to go. If you are planning on 2 harvests, we generally recommend trying to squeeze in a second late one as opposed to an early harvest, as autoflowering genetics are native to Siberia and will finish more reliably in the cold than they will begin in it.
What is the most common plant spacing for autoflowering varieties?
For hemp we are recommending between 8-12k per acre (more or less 1 plant every 4 square feet), and for cannabis we are recommending between 17,500-20k acre (or about 1 every 2 square feet). For example, 1 row on a 30” bed with 12” in-row spacings will come out to roughly 17,424 plants per acre.
Can you transplant autoflowering varieties?
Absolutely, but there is a method that must be applied to ensure yields are not affected. The most common blunder is for farmers to let seedlings go until they are rootbound which is the easiest way to shock one’s plants and greatly reduce their overall yield. The best results we have seen is when plants are transplanted between 7-12 days after sowing. The trick here is to use a cell tray that makes it easy to remove small plants without damaging them. We’ve seen the best results with Growcoons, but there are certainly other options as well (ellepots, ihort, etc).
Can you direct seed autoflowering varieties?
Yes, but again this must be done with proper parameters in place, i.e., seasonal timing, soil type, equipment, and so on. As of yet we have not seen any yield differences between transplanted plants and direct seeded, but we are in the process of collecting massive amounts of data on this. Also, if one plans to do this and they are a beginner, than you will likely need 2-3x the seed to see the emergence you want.
What is the most optimal feeding plan you recommend for autoflowering plants?
We recommend that seasoned full term cannabis growers continue to follow their intuition and hard won skill sets, with one key difference: Normally when full term plants initiate their flowering stage, one switches immediately from vegetative, nitrogen rich fertilizer, to flowering, phosphorous rich bloom formulas. With autos, it is important to continue using vegetative, nitrogen rich recipes until week 6-7, well after they have begun their flowering phase. This is done in order to maximize the canopy as the plants continue to grow vertically and horizontally even as they are putting on flowering sites and bulking up.
After week 6-7, transition to bloom recipes to maximize flower yield and cannabinoid potential. They will put in the majority of their weight in the final 3-4 weeks. As a general rule of thumb, remember that the entire vegetative and flowering cycles of the plant are happening in a 70-80 day period. Some slow release nutrients growers may customarily use may not be appropriate for autos.
If I plant autoflowering plants right next to my full term plants, will it cause my full terms to initiate early flowering?
No, no, and decidedly no. We have heard anecdotal hearsay on this issue but based on experience and understanding the difference in the flowering mechanisms between these genetic lines (ruderalis vs. indica / sativa), we do not believe this is possible.
How long does it normally take before autoflowering plants can be harvested?
Classic autoflowering plants (as opposed to “super auto’s” which take closer to 120 days) can be harvested between 65-90 days depending on the variety and time of year. During peak summer months when the light intensity is higher, autoflowering crops finish faster. During early spring or late fall and especially in a winter greenhouse run, autoflowering plants will take 10-20 days longer to come to full maturity.
What can I expect in terms of biomass yield for each plant?
Between 2-4 ounces, depending on all of the aforementioned factors, i.e., grower skill, genetics, soil health, etc..
What kind of per acre yield can I expect?
This will differ greatly between hemp and cannabis and most markedly depends on your planting densities. For cannabis between 2-5k lbs is common. For hemp between 1-3k lbs. Is common.
How much of my crop can I use as finished, trimmable flower?
This is most probably most dependent on genetics, but anywhere between 25%-100%. Some plants will present uniformly sized buds that are all trimmable throughout the plant, and others will present a variety of different sized buds, some of which will be more appropriately allotted to “smalls” or else sent off for extraction. Again, your breeder should be able to answer this question based on experience.
What can I expect in terms of total cannabinoid content from autos?
This is potentially the most grower skill dependent variable of all, but most of the best auto cannabis genetics around today are at or exceeding 20% THC, which is miraculous if one considers they are taking half as long to bring to harvest. The auto hemp game is vastly different as state by state standards for hot hemp differ greatly, however the best varieties of compliant auto hemp as a population are hitting around 30:1 CBD to THC ratios while remaining compliant. Experienced breeders will know their varieties well enough to be able to recommend optimal harvest times to remain in compliance.
For More Information about Steve Groff, please visit: